1. Field of the Invention
The field of the invention relates to air purifiers, particularly to portable air purifiers including HEPA filters.
2. Brief Description of the Prior Art
Portable air purifiers for removing airborne particles are used in many homes and offices. Such purifiers often include a fine particle high efficiency particulate air (HEPA) filter. In addition to a HEPA filter, some purifiers include a carbon filter to remove odors. The carbon may be incorporated within a fibrous matrix. A filter for trapping relatively large particles may also be found in portable air purifiers. In operation, one or more fans cause air to be drawn through the filter(s) and emitted through an outlet.
HEPA filters have gained increasing acceptance for use in purifiers directed to consumers as they remove 99.97% of particles having a size equal to or greater than 0.3 microns. In order to take full advantage of a HEPA filter or any other type of filter used in an air purifier, it is important to ensure that substantially all of the air emitted by the air purifier has indeed first passed through the filter(s) provided in the purifier. Where a filter includes both a HEPA component and filter component, the lifespan of the filter is generally dependent upon the carbon component. This is because the trapping capacity of the carbon component is generally exhausted prior to that of the HEPA component.
As the filter(s) employed in air purifiers require replacement when spent, the ability to easily remove and replace the filter(s) is important. A replaced filter must be properly installed if it is to function properly. Disposable filter assemblies have accordingly been designed to facilitate user convenience.
Currently portable air purifiers are manufactured in various sizes with different capacities to suit a consumer""s particular needs. The larger capacity air purifiers generally require larger sized filters. This generally requires retailers to stock a plurality of different size filter elements to satisfy the demands of all consumers. Replacement HEPA filter elements are traditionally bulky and expensive inventory for retailers to maintain. The retailer must stock the replacement filters for every air purifier that is sold, but the filters generally do not need replacement very frequently. The retailers that carry air purifiers are required out of necessity to offer a line of different size units that are expensive to purchase, do not turn over very often, and take up a lot of shelf space. In addition, to exacerbate the problem it has been found that by the time the consumer needs to replace the filter element, the inventory is old and looks beat up.
A number of patents have issued which disclose air purifiers including HEPA filters, carbon filters, and/or other filters. U.S. Pat. Nos. 3,928,008; 4,378,983; 4,521,234; 4,629,482; 4,737,173; 4,778,496; 5,078,764; 5,102,435; 5,131,932; 5,230,723; 5,259,854; 5,290,330; 5,512,086; and 5,893,939 disclose air purifiers of various constructions. The disclosure of the U.S. Pat. No. 5,893,939 patent is incorporated herein by reference.
An air purifying device is provided for removing airborne particles. The device includes a housing including an air inlet and an air outlet. A fan is positioned within the housing for drawing air into the housing through the air inlet and expelling air through the air outlet. A filter assembly is positioned within the housing between the air inlet and the fan. The filter assembly includes a frame and a filter element mounted to the frame. The device also includes a hanger and an elongate hanger support that removably extends within the hanger. Either the hanger or the elongate hanger support is coupled to the frame while the other is coupled to the housing.
In a first preferred embodiment, the hanger includes a channel. Preferably the hanger is coupled to an exterior surface of the frame. The hanger is preferably either coupled to a top surface of the frame or alternatively, where the frame includes first and second side surfaces, the hanger is coupled to either the first side surface or the second side surface. The hanger preferably includes at least one pair of converging walls bounding the channel. Preferably the device also includes a second hanger having a channel and a second elongate hanger support that removably extends within the second hanger. Either the second hanger or the second elongate hanger support is coupled to the frame while the other is coupled to the housing.
In a second preferred embodiment, the hanger includes a pair of opposed legs configured to form a gap. The hanger is preferably coupled to an exterior surface of the frame. Preferably the housing includes a door configured to engage the filter assembly. The device also preferably includes a second hanger having a pair of opposed legs configured to form a gap and a second elongate hanger support that removably extends within the second hanger. Either the second hanger or the second elongate hanger support is coupled to the frame while the other is coupled to the housing. Preferably the elongate member includes at least one rib extending within the gap. Preferably the housing includes a wall element attached to the rib.
A filter assembly for removable mounting to an air purifying device is also provided in accordance with the invention. The filter assembly includes a frame, a filter element mounted to the frame, and a hanger coupled to the frame. The hanger removably receives a hanger support mounted to an air purifying device. The frame preferably includes a top wall, a bottom wall, and first and second opposing side walls connecting the top and bottom walls with the filter element being positioned within the walls and the hanger being positioned outside the walls. Preferably, the hanger is either coupled to the top wall or alternatively, to either the first side wall or the second side wall. Preferably the frame is generally rectangular and the channel is generally rectangular in cross section. The filter assembly preferably includes a second filter element. Most preferably, the filter element is a HEPA filter and the second filter element is a removably attached carbon filter.
In an alternative embodiment of the filter assembly, the filter assembly includes a frame, a filter element mounted to the frame, and an elongate hanger support coupled to the frame. The elongate hanger support removably extends within a hanger mounted to an air purfying device. The frame preferably includes a top wall, a bottom wall, and first and second opposing side walls connecting the top and bottom walls with the filter element being positioned within the walls and the hanger support being positioned outside the walls. Preferably, the hanger support is either coupled to the top wall or alternatively, to either the first side wall or the second side wall.